1. Field of the Invention
Archery bows are widely used both for target shooting and for use in hunting wild game. To improve the accuracy of the use of archery bows at different distances from the target, various sighting devices have been devised. Compound hunting bows typically are sold with mounting holes or attachment points on the bow above the bow's hand grip for attaching a sight assembly or assemblies to the bow. This invention relates generally to sighting devices for use with archery bows and more specifically to a back sight assembly which includes a mounting member, support member, receptacle, first rod, second rod, and a sighting member. The back sight assembly is mounted to the bow by means of a mounting member, from which extends a support member. The receptacle slideably engages the support member, and can be effectively adjusted and positively retained in an adjusted position, by means of a first engaging member, at any point along the support member. The first rod is also slideably engaged by the receptacle and it can be effectively adjusted and positively retained in an adjusted position, by means of a second engaging member. The second rod is slideably engaged by the first rod through a hole in the first rod, and can be effectively adjusted and positively retained in an adjusted position by means of a rod engaging member. At one end of the second rod is a sighting member for alignment with the desired yardage pin of the front sight assembly of the bow.
2. History of the Related Art
A variety of different types of sighting devices have been developed for use with archery bows, particularly those used for hunting. The most accurate of such prior art sighting devices employ both front and rear sight members which generally include provisions to compensate for the varying amounts of vertical drop or differing trajectories which occur when the selected targets are at different distances from the archer. While most such prior art bow sights improve the accuracy of a sighted bow over a non-sighted bow, significant disadvantages still result. It is difficult, for example, particularly in a hunting situation when the target is present for a relatively short period of time, to eliminate cant from the bow at the time it is sighted on the target and during the release of the arrow.
Patents which are directed to archery bow sights which include front and rear sight elements for improved accuracy are the U.S. Pat. No. 4,982,503 to Land; U.S. Pat. No. 4,162,579 to James; U.S. Pat. No. 4,417,403 to Strange; U.S. Pat. No. 4,494,313 to Scott; and U.S. Pat. No. 4,542,591 to Montgomery.
The James and Scott Patents disclose front and rear sight platforms which are attached to the bow riser. The rear sight is simply a notch (which is convertible to a circular or "peep" sight in James). The front sight embodies multiple pins located at different vertical spacings corresponding to various distances of the target from the bow. In James, the desired pin must be rotated into place each time a new distance is selected. The rear sight is located in close proximity to the archer's eye and the notch is aligned with the selected bead corresponding to the target distance. It is difficult to accurately align the notch (or the peep hole) with the selected bead, without introducing cant to the proper orientation of the to the archer. Also, in James, the rear sight extends past the string, which presents a problem.
The sight of the Montgomery Patent is similar in some respects to the one of the Scott Patent, but the rear sight is a peep sight which is mounted to the bow riser instead of the string. To use this sight, the bead in the rear or peep sight portion is aligned with a front bead selected to correspond with the shooting distance from the target. A sight of this type is difficult to align under low light conditions; and there is not provision for eliminating or reducing cant in the sight disclosed in the Montgomery Patent.
The fourth Patent of this group is the U.S. Pat. No. 4,417,403 to Strange. The sight of Strange includes a single front bead with a rotatable rear peep sight in which a pair of vertical and horizontal cross-hairs are mounted. The sight disclosed in the Strange Patent may be of some value for target shooting, but it is impractical for hunting. Under hunting conditions where the target distance must be approximated and rapidly selected, insufficient time would exist to adjust the rotational position of the rear sight to obtain any accuracy. Once again, there is no provision in the sight disclosed in the Strange Patent for eliminating or reducing cant of the bow.
The last of the Patent in this group is the Land Patent. The Land Patent is related to a front and rear bow sight system for attachment to an archery bow. It includes an elongated support member for rigid attachment of the sight to the bow, with a front sight member attached to the front of the support member, and a back sight member attached to the rear of the support member. Both the front and the rear sight members contain vertical and horizontal cross-hair pairs. The assembly is adjustable as respects both sight members so that when an archer has pulled the bow to its full draw, and to that archer's normal anchor, the horizontal and vertical cross-hairs of the front and rear sight members are superimposed upon one another. While the dual cross-hairs of the device as disclosed in Land provides a means to reduce cant, the superimposing of one cross-hair upon another in view of the thickness of the cross-hairs, obstructs the view of the archer and does not provide for a precise alignment of the cross-hairs' intersection with the desired yardage pin of the front sight, particularly when the front sight yardage pins are close together.
With specific reference to the back sight of the Land invention, the mounting portion is comprised of a mounting plate or block, a fixed rear extension and a slideable engagement rod moveable thereabout for movement of the sight toward and away from the archer. In addition, the back sight is capable of being adjusted in both the horizontal and vertical planes. The adjustment of the Land invention is accomplished by threading fasteners into spaced pairs of holes in the fixed rear extension. Therefore, continuous adjustment of the back sight along the length of the fixed rear extension is not available. Further, the Land Patent does not teach that its archery bow sight is capable of being mounted to any existing conventional front sight.